1. Field of the Invention
This invention relates to a hydraulic lash adjuster used in a valve train of an internal combustion engine, and more particularly to a hydraulic lash adjuster of the self-contained type in which the fluid is sealed within the assembly without provision for its replenishment from any external source during operation.
2. Description of the Prior Art
In the hydraulic lash adjuster of this type, there is provided an O-ring in an annular groove on a plunger which is slidably mounted in a cylinder member so as to prevent entrance of engine oil into a operating fluid. However, the sliding friction between the O-ring and the cylinder member is relatively so large that the plunger cannot be moved smoothly. Consequently, the reciprocal movement of the plunger is out of accord with an engine operation with resulting that tapet noise is generated due to malfunction of the lash adjuster.